Clean steps

Poor preparation of the substrate can result in loss of adhesion, pitting, roughness, lower corrosion resistance, smears, and stains. Because electroplating takes place at the exact molecular surface of a work, it is important that the substrate surface be absolutely clean and receptive to the plating. In the effort to get the substrate into this condition, several separate steps may be required, and it is in these cleaning steps that most of the problems associated with plating arise. 

Charging bv ion bombardment is the technique used in most mineral separations. The conductive-induction (nonionizing) plate types of separators have also been used Application.s of this device in the minerals indiisti v include its use as a final cleaning step when concentrating rutile and zircon,... 

One of the biggest challenges in this industry is the wide variety of substrates that can be encountered for any given application. Not only can the materials be substantially different in their chemical make up, but they may also be quite different in surface roughness, surface curvature and thermal expansion behavior. To help adhesion to these substrates, preparation of the surface to be bonded may be critical. This preparation may be as simple as a cleaning step, but may also include chemical priming and sanding of the surface. 

As for a gate fee, estimates are difficult to give. Costs are dominated by the investment costs, which Akzo estimates at 25 million for a 50,000 tpa plant. There exists a large uncertainty in this estimate. For instance, if the feed also included brominated or fluorinated compounds, extra cleaning steps would be needed which would greatly enhance the investment. It is simply too early to give a good estimate of costs per toime for treatment. 

Continued decline in performance indicates a membrane cleaning or compatibihty issue. The adequacy of the cleaning step is determined by the recovery of at least 80 percent of the initial normalized water flux. Although some variability in water flux is typical, any consistent dechne reflects an inadequate cleaning procedure. 

Another example of the flexibility of the Pt catalyst is the reconstruction of a stepped Pt(l 11) crystal with adsorbed sulfur upon exposure to CO [25]. Single-crystal Pt(l 1 1) cut at an angle of approximately 5° from the (1 1 1) direction consists of numerous terraces with a width of 20-60 A separated by steps with single-atom height. The adsorption of sulfur atoms restructures the clean stepped Pt(l 1 1) surface with single-atom steps into a sulfur-adsorbed surface with double-atom... 

The type of operation considered in the zero effluent methodology means that the amount of time points used for an operation has to increase. This is due to the fact that there is a processing step and a cleaning step associated with each batch of product. Normally two time points are used to describe a task in a unit. The first time point is used when the task commences in a unit and the second when the task terminates in a unit. In the type of operation considered in the zero effluent models, three time points are used. At the first time point the raw material processing task commences. The raw material processing step ends at the second time point, where the final product is removed and the cleaning operation commences. At the third time point the cleaning operation comes to an end and wastewater is produced. 

Exposure of the clean stepped platinum surface to oxygen caused saturation of the step and kink sites (no adsorption occurred on a 111 surface under identical conditions). The oxygen atom-saturated surface was then exposed to varying amounts of carbon monoxide. Both carbide carbon and CO carbon C Is peaks formed, with a one-to-one correspondence between the growth of carbide and the decrease of surface oxygen atoms. These data are consistent with threee possible reaction schemes ... 

Should a third solvent be added which is immiscible with the other two, then a triphasic system results. The purpose of a third solvent may be, for example, as a built in cleaning step (see below). 

Fig. 3-39 Methanol oxidation current during potential holding after cleaning steps on platinum Nafion SPE and chemically platinized Pt electrodes. 

Potential holding measurements were conducted to examine the sustained current. The surface cleaning steps used for pure platinum were not applied on Pt-Ru electrode because the high potential causes the removal of ruthenium. Instead, the potential was stepped to 800 mV for 5 s for cleaning and stepped to the potential to examine the oxidation current... 

Never allow slurry to dry on wafers. Strong bonds are formed when slurry dries, making the removal of the slurry nearly impossible. The bonds are formed between the abrasive, the abraded pad, the abraded material, and the wafer. The bond strength is such that even supplementary cleaning steps are insufficient to remove the slurry. 

Therefore, an additional cleaning and quality assurance step was used. Columns of 100 mL of resin were prepared and eluted with 200 mL of ether. The ether was then concentrated to 1 mL by Kudema-Danish evaporation and analyzed by a capillary GC with an FID. This analysis showed that many peaks were not removed after 200-fold concentration, and additional resin cleaning steps were needed. Alternate elution of the resin with successive single bed volumes of... 

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